Eczema / Atopic Dermatitis
THE QUICK TREATMENT GUIDE:Author: Howard Shaw, FNP
CONTROL PRURITIS:
Liberal use of oral antihistamines QID not PRN. Hydroxyzine comes as 10mg/5ml and is 5 times stronger than diphenhydramine. Doxepin is a 20 times stronger antihistamine than diphenhydramine. I use hydroxyzine and diphenhydramine for infants and children and use doxepin for adult patients when these others fail.

HYDRATE THE SKIN AND IMPROVE THE SKIN BARRIER AGAINST WATER LOSS:
Encourage daily bathing in tepid water using as little soap as possible and then only a moisturizing soap such as Dove. Other dermatologists recommend cetaphil or oatmeal soap substitutes but I have found these to be too drying. Cover damp skin immediately with petroleum jelly for infants and children. Adults usually prefer a different moisturizer so I recommend Lubriderm. Eucerin and Aquaphor are just as greasy as petroleum jelly and are more costly alternatives. Restoraderm, by Cetaphil, can also be used to repair the skin barrier defect.

TREAT FOR INFECTION IF ERYTHEMA SURROUNDS EXCORIATIONS:
Oral antibiotics such as trimethoprim/sulfamethoxazole for infants and children or Doxycycline for older children, when the risk of teeth staining has passed, and adults will cover MRSA that commonly invades excoriations. Extended use until the pruritis is controlled with antihistamines is necessary.

TREAT THE RASH:
Steroids should be used only on the red or raised areas. It should be emphasized that they should not be used as lubricants and not used on normal skin. We want to avoid systemic absorption, striae, atrophy, and hypopigmentation. For the face and intertriginous areas start with hydrocortisone 1-2.5% or desonide cream or ointments. Fluticasone can also be used for infants and children but is not covered by CCHP. The body rash can be treated with stronger steroids but limit the quantity when prescribing to avoid inappropriate use or over usage. Then step down the strength when control is achieved and stop when the rash has cleared.

Calcineurin inhibitors, such as tacrolimus, can be used as an alternative to steroids. They are especially useful to avoid stronger or prolonged steroid use on the face. These carry a black box warning regarding malignancies that have been seen with the systemic version used as an anti organ rejection drug.

FOLLOWUP:
Infants should be followed up after two weeks. Anyone with cellulitis should be followed after one to two weeks. Others can be followed at monthly or greater intervals to evaluate efficacy and to step down steroid therapy.



THE LONGER STORY
DIAGNOSIS: Atopic dermatitis is a clinical diagnosis. Acute atopic dermatitis is characterized by pruritic, erythematous papules with excoriations and serous exudates with or without vesicles. Sub acute atopic dermatitis is characterized as pruritic erythematous bumpy skin with scaling and some excoriations. Excoriations can be linear or sometimes are 2mm dried crusts made with picking fingernails instead of scratching. Chronic atopic dermatitis has lichenification with increased skin markings, hyper or hypopigmentation from inflammation, and sometimes hyperpigmented nodules called prurigo nodularis. Dennie-Morgan lines, hyperpigmentation of the infraorbital folds can be seen in many atopic patients.
PATHOPHYSIOLOGY: Atopic dermatitis is a combined genetic, environmental, immune system, and skin barrier disorder. IgE levels along and peripheral eosinophils are elevated in most patients. Thirty to eighty percent of patients with atopic dermatitis also have allergic rhinitis and or asthma. Parents are also likely to have this disease. If both parents have atopy then it is likely that their children will have it as well. Although skin tests may produce a response to food allergens, the role of food allergies in the exacerbation of atopic dermatitis remains controversial. Confirmation must be made by food challenges. There are ardent supporters on both sides. T helper 2 lymphocytes are involved in the immune response in atopic dermatitis suppressing T helper 1 response to infections. Likewise T helper 1 response to infections suppresses T helper 2 production. This is why it has been proposed that early exposure to bacteria and viruses can decrease allergies in this population.
CLINICAL PRESENTATION: PRURITIS is a major component of atopic dermatitis. Atopic dermatitis is sometimes called the itch that rashes! Neuropeptides, leukotrines, basophiles, eosinophils, and histamine increases may be responsible for the pruritis.
Without controlling the scratching or rubbing behavior that atopic dermatitis cannot be controlled. Infants have red rough cheeks because they can move their faces and rub them when breast feeding, against mattresses, etc. The wrists are easily reachable and both the volar and dorsal wrist areas are commonly involved. Babies roll their bodies to scratch their torsos. Once the toddler attains hand control the antecubital and popliteal fossae become involved.
Increased transepidermal water loss accounts for the dry rough skin of atopic patients. This may be due to the decreased production of filaggrin and ceramides. Thus improving the hydration of the skin is paramount. Water evaporation can increase drying of the skin. Bathing without trapping the water can worsen the xerosis. It is best to avoid lotions, which contain water, in favor of ointments or creams.

(from information provided by Howard Shaw, January 2011, with very slight formatting modifications from Tai Roe)